1. Field of the Invention
The subject invention relates to medical devices and, more particularly, to hypodermic syringes with protective needle guards.
2. Description of the Invention Background
Syringes equipped with hypodermic needles are commonly used to inject precise amounts of medicament subcutaneously. In the past, hypodermic needles were provided with a removable needle shield that encased the needle prior to use. To use the syringe, the shield was removed from the needle and retained by the user so that it could be replaced after the injection had been completed. Replacement of the shield on the contaminated needle was fraught with risk and required extreme care on the user's part to avoid inadvertent sticks by the contaminated needle. Furthermore, if the user lost or misplaced the shield during the injection process or otherwise failed to replace it after use, the syringe was disposed of with an exposed contaminated needle.
Over the years, healthcare professionals recognized these problems and consequently several different types of needle guards were developed. For example, U.S. Pat. No. 2,571,653 to Bastein, U.S. Pat. No. 4,631,057 to Mitchell, U.S. Pat. No. 4,725,267 to Vaillancourt, U.S. Pat. No. 4,731,059 to Wanderer et al., and U.S. Pat. No. 4,804,372 to Laico et al. all disclose various types of needle shield arrangements that are mounted on a portion of the syringe and that purport to eliminate the problems associated with replacing the guard after the needle has been used. While many of such inventions effectively addressed the problems of inadvertent needle sticks, such inventions were often difficult to economically fabricate and/or difficult to use. Thus, they were not readily embraced by the healthcare community.
Existing needle guard assemblies also have other shortcomings. For example, many of such guards are slidably supported on the syringe, but lack a mechanism for retaining the needle guard in its extended position wherein it fully protects the needle. However, the needle guard disclosed in U.S. Pat. No. 5,609,584 to Gettig et al. solved such problem. Such shield could be easily retracted to expose the needle for injection purposes and thereafter be extended over the needle and releasably retained in that position until needed for the next injection or until the needle was disposed of.
In recent years, however, with the increasing concerns regarding the spread of diseases such as AIDS and hepatitis through inadvertent needle sticks, some governmental agencies have recognized the desirability of a needle guard that can be releasably latched in a needle-guarding position between the time the medicament is drawn into the syringe and the time the medicament is injected into the patient or between consecutive injections into the same patient while also having the ability to permanently lock the guard in the needle-guarding position for safe disposal of the needle.
Thus, there is a need for a guard for a hypodermic needle that can be releasably latched in a needle-guarding position between injections and that also has the capability of being permanently locked in such position to render the needle unusable for further injections and for safe disposal thereof.
There is a further need for a needle guard having the above-mentioned attributes that can be economically manufactured and is easy and safe to use.
Yet another need exists for a needle guard assembly that has the above-mentioned attributes and that can be readily constructed for use with a variety of types and sizes of syringes.